I think I got the error.
it must be.
$WAFV_Errors .= WAValidateDT(((isset($_POST["year"]))?$_POST["year"]:"").'-'.((isset($_POST["month"]))?$_POST["month"]:"").'-'.((isset($_POST["day"]))?$_POST["day"]:"") . "",true,"\b\d{4}-(1[0-2]|0[1-9])-([12]\d|3[0-1]|0[1-9])\b","","".(date("Y-m-d", mktime(0, 0, 0, date("m"), date("d"), date("Y") - 18))) ."",false,".*","","",true,8);
maybe someone can check this :-)))